Coastal Region Of South Korea Research Articles

Levels and profiles of perfluorinated alkyl acids in liver tissues of birds with different habitat types and trophic levels from an urbanized coastal region of South Korea

Contamination status and characteristics of perfluorinated alkyl acids (PFAAs) including perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs) was examined using liver tissue of birds - black-tailed gulls (Larus crassirostris), domestic pigeons (Columba livia var. domestica), pacific loons (Gavia pacifica), herons (Ardea cinerea), and egrets (Egretta garzetta and Ardea alba) - with different trophic levels, habitat types and migratory behaviors from an industrialized coastal region of South Korea. A wide range of PFAAs (1.09 ng/g to 1060 ng/g; median = 52.6 ng/g) were detected in bird livers from the Korean coasts with high detection frequency. Accumulation features of PFAAs in birds indicated that primarily trophic position and secondly habitat type influence the levels and composition of PFAAs, e.g., relatively high PFAA levels and high composition of odd-numbered long carbon chain PFCAs (perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTriDA)) and PFOS in higher trophic and marine birds. The prevalence of long carbon chain (≥14) PFCAs likely implies a wide use of fluorotelomer-based substances in Korea. Interspecies comparison in the accumulation profile of persistent organic pollutants (including polychlorinated biphenyls (PCBs), organochlorine pesticides, polybrominated diphenylethers (PBDEs), and PFAAs) reveals relatively high load of PFAAs in inland (pigeons) and estuarine (egrets/herons) species compared to marine bird species, indicating wide use of PFAAs in the terrestrial environment.

Temporal and Spatial Variations of the Biochemical Composition of Phytoplankton and Potential Food Material (FM) in Jaran Bay, South Korea

Food material (FM) derived from biochemical components (e.g., proteins, lipids, and carbohydrates) of phytoplankton can provide important quantitative and qualitative information of the food available to filter-feeding animals. The main objective of this study was to observe the seasonal and spatial variations of the biochemical compositions of phytoplankton and to identify the major controlling factors of FM as a primary food source in Jaran Bay, a large shellfish aquaculture site in South Korea. Based on monthly sampling conducted during 2016, significant monthly variations in the depth-integrated concentrations of major inorganic nutrients and chlorophyll a within the euphotic water column and a predominance (49.9 ± 18.7%) of micro-sized phytoplankton (>20 μm) were observed in Jaran Bay. Carbohydrates were the dominant biochemical component (51.8 ± 8.7%), followed by lipids (27.3 ± 3.8%) and proteins (20.9 ± 7.4%), during the study period. The biochemical compositions and average monthly FM levels (411.7 ± 93.0 mg m−3) in Jaran Bay were not consistent among different bays in the southern coastal region of South Korea, possibly due to differences in controlling factors, such as environmental and biological factors. According to the results from multiple linear regression, the variations in FM could be explained by the relatively large phytoplankton and the P* (PO43− − 1/16 × NO3−) and NH4+ concentrations in Jaran Bay. The macromolecular compositions and FM, as alternatives food source materials, should be monitored in Jaran Bay due to recent changes in nutrient concentrations and phytoplankton communities.

Characterization and phylogenetic analysis of the complete mitochondrial genome of the marine ribbon worm Cephalothrix species (nemertea: Palaeonemertea)

Here, we report the complete mitochondrial genome of the marine nemertean Cephalothrix species collected from the coastal region of South Korea. The mitochondrial genome of Cephalothrix sp. South Korea (SK) stain is 16,396 bp contains 13 protein-coding genes (PCGs) along with 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and an AT-rich noncoding region, arranged identically to those of Palaeonemertea. The nucleotide composition in the Cephalothrix sp. (SK) mitogenome is highly biased toward A and T as total AT content is 76.3% across the genome. A phylogenetic analysis of Nemertean species indicates that Cephalothrix sp. (SK) mitogenome shows close relationships to those of Palaeonemertea (Cephalothrix sp. and C. hongkongiensis collected from China).

Potential distribution analysis of an invasive alien species Parapediasia teterrella (Lepidoptera, Crambidae) in East Asia

Abstract The bluegrass webworm moth Parapediasia teterrella (Zincken, 1821) is a notorious pest that is native to North America. However, it has invaded East Asia and has caused serious economic losses in China and Japan. The objective of this paper is to analyse the potential geographic distribution of P. teterrella in East Asia with MaxEnt, using predictor variables related to temperature and precipitation. It is suggested that this species has potential to establish in Southeast China, most areas of Jeollanam-do, eastern coastal region of South Korea, and most areas of Japan. Furthermore, we applied the Jackknife test to evaluate the significance of climatic variables in modelling the potential distribution of P. teterrella. The result indicates that annual mean temperature (Bio1), mean temperature of the coldest quarter (Bio11) and precipitation of the coldest quarter (Bio19) mainly affect its geographical distribution. A map showing the potential distribution of P. teterrella in East Asia is provided, and morphological diagnosis of the species is also given.

Delineation of high resolution climate regions over the Korean Peninsula using machine learning approaches.

In this research, climate classification maps over the Korean Peninsula at 1 km resolution were generated using the satellite-based climatic variables of monthly temperature and precipitation based on machine learning approaches. Random forest (RF), artificial neural networks (ANN), k-nearest neighbor (KNN), logistic regression (LR), and support vector machines (SVM) were used to develop models. Training and validation of these models were conducted using in-situ observations from the Korea Meteorological Administration (KMA) from 2001 to 2016. The rule of the traditional Köppen-Geiger (K-G) climate classification was used to classify climate regions. The input variables were land surface temperature (LST) of the Moderate Resolution Imaging Spectroradiometer (MODIS), monthly precipitation data from the Tropical Rainfall Measuring Mission (TRMM) 3B43 product, and the Digital Elevation Map (DEM) from the Shuttle Radar Topography Mission (SRTM). The overall accuracy (OA) based on validation data from 2001 to 2016 for all models was high over 95%. DEM and minimum winter temperature were two distinct variables over the study area with particularly high relative importance. ANN produced more realistic spatial distribution of the classified climates despite having a slightly lower OA than the others. The accuracy of the models using high altitudinal in-situ data of the Mountain Meteorology Observation System (MMOS) was also assessed. Although the data length of the MMOS data was relatively short (2013 to 2017), it proved that the snowy, dry and cold winter and cool summer class (Dwc) is widely located in the eastern coastal region of South Korea. Temporal shifting of climate was examined through a comparison of climate maps produced by period: from 1950 to 2000, from 1983 to 2000, and from 2001 to 2013. A shrinking trend of snow classes (D) over the Korean Peninsula was clearly observed from the ANN-based climate classification results. Shifting trends of climate with the decrease/increase of snow (D)/temperate (C) classes were clearly shown in the maps produced using the proposed approaches, consistent with the results from the reanalysis data of the Climatic Research Unit (CRU) and Global Precipitation Climatology Centre (GPCC).

Climate change impact on typhoon-induced surges and wind field in coastal region of South Korea

Typhoon-induced strong wind is a main factor leading local, weather-related sea-level rise with respect to the global climate change i.e. intensity and frequency of typhoon. This research mainly focuses on obtaining key relations of typhoon-induced wind and surges due to the increase of typhoon intensities. To obtain the winds and surges due to the climate change, this research has employed a dynamic surge model SLOSH (Sea, Lake, and Overland Surges from Hurricanes) which solves two-dimensional Navier-Stokes equations with wind obtained computation of pressure and wind direction for given stationary and circularly-symmetric storm as surface stress. Because of less expensive computational cost, it is suitable model for estimating typhoon-induced wind and surge heights with respect to the highly categorized hypothetical typhoons due to global warming. The hypothetical typhoons are composed by increasing mean sea level pressure (MSLP) and choosing corresponding radius of maximum wind (RMW) along a path of historical typhoon MAEMI (2003). The increment of MSLP resulted in the decrease of the maximum wind speed by same decline rations without dependence on the local characteristics. However, the typhoon-induced surge heights are strongly depending on the typhoon intensity and the local bathymetry. In addition, a comparison of numerically estimated wind to observational data resulted in ±50% error bounds which are corresponding to residuals appeared in the typhoon-induced surge heights.

Application of SLOSH in estimation of Typhoon-induced Storm Surges in the Coastal Region of South Korea

Seo, J.; Ku, H.; Cho, K.; Maeng, J.H., and Lee, H., 2018. Application of SLOSH in estimation of Typhoon-induced Storm Surges in the Coastal Region of South Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 551–555. Coconut Creek (Florida), ISSN 0749-0208.SLOSH (Sea, Lake, and Overland Surges from Hurricane) is a dynamic tropical surge model forecasting real-time storm surges by solving two-dimensional Navier-Stokes equations with hydrostatic approximation. To apply this model SLOSH on estimating the typhoon-induced storm surges around Korean coastal regions, a two-dimensional hyperbolic domain covering the East, the West and the Southern Seas of Korea is developed. The grid resolution is as high as approximately 500m at the coast and extended to about 4.2km far away ocean. By adopting 30-m digital elevation map SKKU DEM which has an advantage on connectivity between land and ocean and KorBathy30s which is 30 seconds gridded bathymetry of Korea marginal seas, the local characteristics are considered on the shape of continental shelf of the East Sea, the West Sea, and the Southern Sea. This SLOSH input domain for Korea is examined by applying for three strong, historical typhoons, THELMA(1987), FAYE(1995), RUSA(2002), MAEMI(2003), MEGI(2004) and SANBA(2012) and comparing to observational storm surges at two tidal station located in southern coastal cities of Tongyeong and Yeosu, South Korea. The SLOSH reproduced well the typhoon-induced surge pattern which dramatically increased and suddenly drop as the typhoons are passing through the stations. In case of typhoon MAMEMI(2003) which recorded almost 170cm of typhoon-induced surge height, the model SLOSH estimates it with less 1% error. At this station, the root-mean-square is shown as 27.92.

Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary

Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral ∑PFASs were within the range of 76–551pg/m3. Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%–95% of neutral ∑PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral ∑PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition were simulated for neutral PFASs, and neutral ∑PFASs fluxes varied from 0.37 to 2.3pg/m2/s. In the dissolved phase of the surface water, concentrations of ionic ∑PFASs ranged from 1.6 to 118ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%–90% of the ionic ∑PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic ∑PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs.

Oceanisphaera aquimarina sp. nov., Isolated from Oil-Contaminated Sediment of Ocean Coastal Area from South Korea.

Strain S33(T) was isolated from oil-contaminated sediment of Tae-an coastal region of South Korea. Cells are aerobic, motile, Gram staining-negative, and coccoid shaped. Strain S33(T) grew optimally at the temperature of 25°C (range of 4-40°C), pH 6.0 (range of pH 6.0-10.0), and in the presence of 1% (w/v) NaCl (range of 0-10%). Ubiquinone-8 was the predominant respiratory quinone. C16:0, summed feature 3 (comprising C16:1ω7c/C16:1ω6c) and C18:1ω7c were the major fatty acids. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. Strain S33(T) showed the ability to degrade benzene, toluene, and ethylbenzene after 3days incubation. 16S rRNA gene sequence analysis showed that the strain S33(T) was most closely related to Oceanisphaera sediminis TW92(T) (97.3%), Oceanisphaera profunda SM1222(T) (97.2%), and Oceanisphaera ostreae T-w6(T) (97.1%) and <97% with other members of the genus Oceanisphaera. The genomic DNA G+C mol% content of strain S33(T) was 51.0mol%. Based on distinct phenotypic, genotypic, and phylogenetic analysis, strain S33(T) was proposed to represent a novel species in the genus Oceanisphaera as Oceanisphaera aquimarina sp. nov. (=KEMB 1002-058(T)=JCM 30794(T)).

Levels and profiles of persistent organic pollutants in resident and migratory birds from an urbanized coastal region of South Korea

Persistent organic pollutants (POPs) levels in resident and migratory birds collected from an urbanized coastal region of South Korea were investigated. As target species, resident birds that reside in different habitats—such as inland and coastal regions—were selected and their POP contamination status and accumulation features evaluated. Additionally, winter and summer migratory species were analysed for comparison with resident birds. Black-tailed gull and domestic pigeon were selected as the coastal and inland resident birds, respectively, and pacific loon and heron/egret were selected as the winter and summer migratory birds, respectively. The overall POP concentrations (unit: ng/g lipid) in resident birds were 14–131,000 (median: 13,400) for PCBs, 40–284,000 (11,200) for DDTs, <1.0–2850 (275) for CHLs, 23–2020 (406) for HCHs, 2–1520 (261) for HCB, <0.2–48 (5) for pentachlorobenzene (PeCB), 71–7120 (1840) for PBDEs, and <1.8–2300 (408) for HBCDs. In resident birds, the overall level of POPs was higher in seagull compared to pigeon. The stable isotope ratio of nitrogen and carbon indicates that seagull occupies a higher trophic position in the environment than pigeon. However, the POP accumulation profiles in these species differed. Pigeon tends to accumulate more recently used POPs such as PBDEs than seagull. The high-brominated BDE congeners, γ-HBCDs and γ-HCH (also called lindane) were enriched in pigeon compared to seagull, implying the widespread use of Deca-BDE, technical HBCDs, and lindane in the terrestrial environment of South Korea. The different accumulation profile of POPs in both resident species would be related to their habitat difference and trophic positions. For urban resident bird such as pigeon, an intentional intake of dust or soils during feeding is likely to be an additional route of exposure to POPs. Resident birds generally accumulated higher POPs concentrations than migratory birds, the exceptions being relatively volatile compounds such as HCB, PeCB and HCHs.

Statistical Soil Erosion Model for Burnt Mountain Areas in Korea—RUSLE Approach

The objective of this paper is to develop a model to estimate soil erosion based on data from natural rainstorms on the hillslopes of burnt mountains. For this research, 52 plots were established on mountain slopes in the eastern coastal region of South Korea and operated for 6 years after the fire. Runoff and soil erosion were influenced greatly by rainfall and vegetation factors, respectively. The vegetation index that reflects the structure of vegetation recovered after the forest fire and the soil index that reflects soil characteristics in burnt forest lands showed higher correlations than factors of the revised universal soil loss equation (RUSLE). Sediment yield decreased generally with increasing slope steepness and length because of the effects of depression storage and flow interception by stems and litter on forest lands. The Soil Erosion Model for Mountain Areas in Korea (SEMMA), used to compute sediment yield from hillslopes, is a statistical model composed of four variables: rainfall, vegetation cover, soil, and topography. According to sensitivity analysis for each parameter, rainfall and vegetation showed high sensitivities. The SEMMA model was improved by developing several equations that were classified by rainfall depth and vegetation coverage. This model may be applied usefully to assess soil erosion risks in burnt mountains.

Characteristics of particle formation events in the coastal region of Korea in 2005

Measurements of particle number size distribution with diameters ranging from 10 to 487nm, meteorological parameters and two pollutant gases (ozone (O3) and sulfur dioxide (SO2)) were made to investigate characteristics of new particle formation and growth events at the western coastal region of South Korea in 2005. Among 291 days of Scanning Mobility Particle Sizer (SMPS) measurements, 56 days (about 19.2%) were identified as particle formation events. In particular, 48 days were classified into significant nucleation events. During the cold season, the events are most frequently occurred. Particle growth rates during the cold season were in the range of 1.0–15.7nmh−1 with the mean of 5.9nmh−1.Most of the nucleation events were observed at the conditions of high UV-B irradiance (>50mWm−2) and low relative humidity (<60%). The SO2 concentration on nucleation event days was higher than that of non-event days, whereas the O3 concentration between event and non-event days did not show any significant difference. The nucleation events were also found to be associated with a sea breeze blown from northwest or southwest direction, indicating that the air masses may be originated from the Asian continent and accompanied with cold air outbreak behind cold fronts.